Pretty Permalinks – not in search results (google)

Here’s a pretty basic one (from someone who clearly doesn’t understand Pretty Permalinks and site indexing!):

I have implemented Pretty Permalinks a handful of months ago and all is working well…

When I go to Google to check out what pages have been indexed, I see both non-pretty and also pretty permalinks.

I am wondering
1. if that impacts google searches (and site rankings) and how to clean it up if it matters
2. when a pretty permalink URL is displayed vs when is a non-pretty URL is displayed in results

Thanks much!